Crestor (rosuvastatin) is a widely prescribed cholesterol-lowering statin, and most people tolerate it well. But like all statins, it carries a range of potential side effects, from common and mild issues like headaches and muscle aches to rare but serious complications including muscle breakdown and kidney problems. In clinical trials, the most frequently reported side effects affected fewer than 4% of participants.
Common Side Effects
In controlled clinical trials, the five most common side effects were headache (3.7% of participants), muscle pain (3.1%), abdominal pain (2.6%), weakness or fatigue (2.5%), and nausea (2.2%). These numbers mean the vast majority of people taking Crestor won’t experience any of them, and when they do occur, the symptoms are typically mild enough that most people continue treatment.
Muscle Problems
Muscle-related side effects are the most talked-about concern with any statin, and Crestor is no exception. The mildest form is muscle aching, soreness, stiffness, or cramping, sometimes described as a flu-like feeling. Observational studies put the rate of these symptoms anywhere from 5% to 25%, a wide range partly because muscle aches are common in everyday life and hard to attribute definitively to the medication.
More serious muscle damage is genuinely rare. In clinical trials, about 3 in 10,000 patients developed severe muscle disease. The most dangerous form, rhabdomyolysis, occurs when muscle tissue breaks down rapidly and releases proteins that can damage the kidneys. Rhabdomyolysis from statins is potentially fatal, but deaths are extremely rare, occurring in roughly 1 per 6.6 million prescriptions. If you develop unexplained muscle pain, tenderness, or weakness, especially with dark-colored urine or fever, that warrants prompt medical attention.
Diabetes Risk
Crestor can nudge blood sugar levels upward. In the large JUPITER trial, 3.0% of people taking rosuvastatin developed new-onset diabetes over about two years, compared with 2.4% on placebo. That’s a real but modest difference. A separate analysis found that rosuvastatin users had a 42% higher relative risk of developing diabetes compared to non-users, one of the higher rates among statins.
For people who already have diabetes, the effect on blood sugar control is small but measurable. High-dose rosuvastatin (40 mg) raised HbA1c, a marker of average blood sugar over two to three months, by about 0.3% over 18 weeks. Across all statins and doses, a large meta-analysis of 23 trials found an average HbA1c increase of 0.11%. Higher statin doses tend to push blood sugar up more than lower doses. For most people, the cardiovascular benefits of statins outweigh this modest metabolic trade-off, but it’s worth monitoring if you’re already at risk for diabetes.
Liver Effects
Statins can occasionally cause liver enzyme elevations, a sign of liver irritation. The FDA recommends considering liver enzyme testing before starting Crestor and repeating it when there’s a clinical reason to check. Routine periodic monitoring is no longer required for most patients, a change from earlier guidelines that reflects how uncommon significant liver injury actually is with statins. Symptoms like unusual fatigue, loss of appetite, dark urine, or yellowing of the skin or eyes would be reasons to get tested.
Kidney Concerns at Higher Doses
There is a dose-related increase in protein and blood appearing in the urine with rosuvastatin, starting at about 1.3% of patients on the 40 mg dose. Among patients who showed these urine changes, the percentage with a meaningful rise in creatinine (a marker of reduced kidney function) climbed with each dose level: 14% at 5 mg, 16% at 10 mg, 24% at 20 mg, and 33% at 40 mg. This is one reason the highest dose is reserved for people who genuinely need it and is not typically a first-line choice.
Memory and Cognitive Effects
Some statin users report foggy thinking or memory problems. The FDA has acknowledged cognitive side effects as a class-wide concern for statins, though the evidence in humans remains mixed. Animal research has shown that very high doses of rosuvastatin can impair learning and memory by reducing levels of growth factors in the brain’s memory center. In practice, these cognitive complaints are uncommon and appear to be reversible when the medication is stopped. If you notice new confusion or memory lapses after starting Crestor, it’s worth discussing with your prescriber.
Dosing Differences for People of Asian Descent
The FDA recommends that people of Asian descent start rosuvastatin at half the usual dose. This isn’t a difference in sensitivity or tolerance in the traditional sense. It’s pharmacokinetics: studies show that Asian patients have roughly twice the blood levels of rosuvastatin compared to white patients given the same dose, likely due to differences in drug transport proteins. Starting at a lower dose achieves the same effective drug exposure, which also reduces the risk of dose-dependent side effects like muscle problems and kidney changes.
Drug Interactions That Increase Risk
Certain medications dramatically increase the amount of rosuvastatin circulating in your blood, which amplifies the risk of muscle damage and other side effects. The most significant interactions include:
- Cyclosporine (an immune-suppressing drug): increases rosuvastatin blood levels about 7-fold
- Certain hepatitis C antivirals: some combinations raise levels up to 7.4-fold
- Gemfibrozil (another cholesterol drug): nearly doubles rosuvastatin levels and independently raises muscle damage risk
- Some HIV medications: can triple rosuvastatin exposure
Other drugs that increase risk include colchicine (used for gout), niacin at prescription doses, fenofibrate, and ticagrelor (a blood thinner). Cases of rhabdomyolysis have been reported specifically in patients taking Crestor alongside ticagrelor. If you take multiple medications, your prescriber should check for interactions before adding or adjusting rosuvastatin.
The FDA label notes that rosuvastatin is processed through specific enzymes and transport proteins in the body. Any drug that inhibits these pathways can cause rosuvastatin to accumulate, turning a safe dose into an effectively higher one. This is why the same 10 mg pill can behave very differently depending on what else you’re taking.